Protractor



PRoTRAcToR. APPLICATION FILED'MAYZOI 1920.

sm', Patented May 16,1922.

@FFEQM FRANK essere KNUUSI, or nunon MOUNTAIN, MICHIGAN.

PROTBAACTOR,

Application filed. May 20, 1920, Serial No. 882,774.

To all whom t may concern:

Be it known that I, FRANK OSCAR KNUUsI, a citizen of the United States, residing at Huron Mountain, in the county of Marquette and State of Michigan, have invented a certain new and useful Improvement in Protractors, of which the following is a specification. y

rThis invention is a protractor device adapted to many uses, but especially designed for use by carpenters' and builders in marking boards or other timbers preparatory to cutting them to conform to irregular surfaces such for instance as the walls of a log house against which it is desired they shall lit.

The object of the inventionis to provide 'a device of this character with which an operator can by laying the board which is to be cut against the wall which it is to lit, and running the device of this invention over it so mark the board that it can be cut to accurately fit the wall.

The invention consists in means for carrying out the foregoing objects which can be easily and cheaply made, which is eflicient in use, and is not readily liable to get out of order. More particularly the invention consists in features and details of construction more fully set forth in the specification and claims,

Referring to the drawingsA in which similar numerals represent the same parts throughout the several views.

Figure 1 is a perspective view showing the board and the log wall to which it is to be applied and the mechanism of this invention inoperative relation thereto.

Figure 2 is a sectional end view of the pencil holder mechanism'.

`Figure 1 shows two logs 10 and 12 of Van imaginary log building wall to which it is desired to tightly fit a board 14 preparatory to building a board wall at right angles to the log wall. The tool provided by this invention for properly marking the board happens to be applied to a carpenters trisquare having the usual graduated long arm 16 and short arm 18, but the tri-square as such forms no real part of this invention. The main thing about the tri-square is that its long arm 16 is provided with a transverse flange 20 which bears against the straight edge of the board 14 to guide the tri-square up and down that edge of the board and that the short arm 18 of the trisquare Vis provided with a longitudinal slot 22 which guides the sliding rod 24 as it moves in and out perpendicular to the edge of the board 14 and the vlong arm 16 of the trisquare.y F or purposes of giving this sliding bar 24 additional support the short arm 18'of the tri-square is provided with a supplemental rearwardly extending arm 26 sustained from the long arm 16 of the tri-square by a diagonal brace 28.

The sliding rod 24 is provided at its end toward the log wall, hereafter referred to as the working end, with a point 80, preferably tapered to sutlicient thinness so that when in the full line position of Figure 1 it will enter between the logs 10 and 12 to as great a distance as it can possibly be hoped that a portion of the board 14 can be made to enter. Along the rod 24 at suitably short intervals are a series of perforations 32 adapted to be entered by a suitable pencil 34. ln the particular case here illustrated this pencil is detachably insertable in the pencil holder 36 which has on its lower end a projecting lug 38 detachably fitting in perforations 32 in rod 24. This structure is such that any part of rod 24 which carries the pencil 34 may travel back through arm 18 as is necessary in tracing those parts of lines 40 and 42 which lie to the left of the end of said arm 18, without being in any way stopped by the presence of the pencil. The pencil 34 may7 if desired, be detachably secured in the pencil holder by set screw 40.

In the operation of the device the operator after firstl placing the board 14 against the logs as shown places the instrument with the tri-square and the rod 28 in the position shown in full lines in the drawing so that withthe flange 20 bearing on edge 21 of the board the point 3() of the rod 24 is as far as it willconveniently go between the two adjacentjlogs 12l and 14 of the whole wall which has the deepest notch or recess between them. In this position the operator adjusts the pencil holder in the hole 32 which is opposite or nearest opposite the left hand edge 46 of board 14. He then moves the trisquare along edge 21 of the board 14 in the direction in which marking is to be done, holding the lia-nge 20 of the tri-square solidly against the board as the tri-square moves. As the rod 24 was at the start way in between the logs it is impossible to carry out this movement of the tri-square described without the operator taking hold of the pencil at the handle and moving the rod 24 outward so that it at least no more than touches the log. By holding the point 30 of the rod 2li in contact with the adjacent circumference of the log, as the tri-square is moved the pencil point will trace on the board lll a line corresponding to the exact shape of the log which is followed. ln the drawing the device is supposed to have traced the line ll0 corresponding to the semicircumference oil log l() before reaching the point shown in full lines from which it is about to tracefline 4:2, corresponding to the semi-circumierence ot the log l2. The dotted line portion oi" Figure l shows the position ot' the point 3() ot the rod Qf-l and the short arm 18 olf the tri-square when the device has moved down sutl'iciently to be marking line l2 at a point approxin'iately opposite the center of the log l2.

After the board 14 is marked with lines l() and fl-2 corresponding to the respective logs, proper tools can be used to cut vaway Jdie board portions to the right of these lines L() and 4t2 whereupon the surface edge oli the board adjacent to thc wall will be exactly the proper shape to accurately fit each log of the wall.

Byy rigidly securing rod 24e in one position in the tri-square, as for instance by the use of a set screw 47, the device may be used to cause the pencil Sli to mark a straight line on the board i/ l parallel to the side oil" the board which is engaged by the vflange 2O while thc tri-square is moved down the board. This is oft use in marking the board for straight ripping in the ordinary manner.

By removing the rod i'rom the trisquare and pivoting it at any one of the holes 32 which may be selected, the device may be used as a compass tor drawing circles around the particular point selected.

lt will be observed that when l specify in the claims a pencil device carried by and movable with the rod to effective marking positions within the marginal limits of the member, such expression shall be construed as meaning that the pencil 3ft is movable to effective marking positions disposed entirely between all marginal edges of the member or arm which carries the pencil supporting rod 24.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is

l. ln mechanism of the class described, a member adapted for movement along the edge et an article to be marked, a rod slidably mounted on the member for movement at an angle to the direction of operative movement of the member, and a pencil device carried by and movable with the rod to effective marking positions within the marginal limits of the member.

2. 'ln mechanism of the class described, a guide member adapted to travel along the ledge olf a board to be marked, a rod slidable in the guide member at an angle to the direction ot operative movement of the member, and a pencil device carried by the rod and adjustable with respect thereto to effective marking positions within the marginal limits of the guide member.

3. ln mechanism ot the class described, tri-squame, having on one arm a flange for engagement with the edge of a board, a rod slidably supported by the other arm of the tri-square ilior movement at an angle to the first arm, and a pencil device adjustably carried by the rod and movable with the latter to effective marking positions within the marginal limits oie the second arm.

fl. ln mechanism of the class described, a trisquare having a relatively long arm with a projecting Vflange thereon, another arm eX- tending across the end ot the first arm and on both sides thereof, means for bracing one end of the second arm from the first arm, rod slidable in and guided by the second arm at right angles to the first, and having a point, there being in said rod along its length a series o'f periiorations iior the reception ci" a pencil point, and a pencil holder adapted to be detachably inserted in a selected one of said holes, so that the point of the pencil inserted therein will pass through said rod and mark on a surface below said rod, all the parts being arranged, shown and described for thepurposes set forth.

In witness whereof, l have hereunto subscribedmy name in the presence of two witnesses.

FRANK OSCAR KNUUS.

lVitnesses 

